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Describe the impact of deforestation of both abiotic and biotic factors within the tropical rainforest.

The fluid mosaic model of the membrane proposed that membranes

Which of the following must be true for a fossil organism to be useful as an index fossil? a. the fossil organism must be widespread geographically. b. the fossil organism must be abundant. c. the fossil organism must be limited to a short span of geologic time. d. all of the above.